Abstract:Objective：Through diagnosis-related group(DRG) to evaluate the internal medical service performance in a certainhospital，toprovide a basis for continuously improving the medical service and promoting the refined management of hospital. Methods：Using the synthetic index method and theRank-Sum-Ratio(RSR) method to evaluate the performance of 20 medical departments from three aspects，namely service capability，service efficiency and medical safety. Results：The top three departments whose composite index values were best were Department of RespirationⅠ，Department of CardiologyⅠ，and Department of Medical OncologyⅠ. The last three departments were Department of Rehabilitation，Department of Geriatrics and Department of NeurolgyⅠ. Three grades of the medical service performance，namely Good，Average and Poor，were divided by the RSR method. Department of RespirationⅠ，Department of CardiologyⅡ，Department of CardiologyⅠ，and Department of Medical OncologyⅠ were divided into Good.Department of Rehabilitation，Department of NeurolgyⅠand Department of Geriatrics were divided into Poor. The other departments were divided into Average. Conclusions：Defects of different degrees of the departments were observed in the service capability，efficiency and safety. Based on one’s own weakness，targeted improvements should be taken in order to improve the overall medical service level.